acegi构造安全的java系统

				package sample.dms;								/**				 *				 * @author Ben Alex				 * @version $Id: Directory.java 1784 2007-02-24 21:00:24Z luke_t $				 *				 */				public class Directory extends AbstractElement {				    public static final Directory ROOT_DIRECTORY = new Directory();								    private Directory() {				        super();				    }								    public Directory(String name, Directory parent) {				        super(name, parent);				    }								    public String toString() {				        return "Directory[fullName='" + getFullName() + "'; name='" + getName() + "'; id='" + getId() + "'; parent='" + getParent() + "']";				    }				    				}